Fast elements conversions in crankshaft using generated code.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index ab582a2ba9440541ac90b2054ddd31061920289c..428fa2ec2714e9c54e66ad704922bff4054fa877 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -1030,6 +1030,11 @@ class ToBooleanStub: public CodeStub {
 
 class FastElementsConversionStub : public CodeStub {
  public:
+  enum Type {
+    TRANSITION_ONLY,
+    TRANSITION_AND_STORE
+  };
+
   FastElementsConversionStub(ElementsKind from,
                              ElementsKind to,
                              bool is_jsarray,
@@ -1039,8 +1044,18 @@ class FastElementsConversionStub : public CodeStub {
         is_jsarray_(is_jsarray),
         strict_mode_(strict_mode) {}
 
+  static void GenerateSmiOnlyToDouble(
+      MacroAssembler* masm,
+      Type type,
+      StrictModeFlag strict_mode = kInvalidStrictFlag);
+
+  static void GenerateDoubleToObject(
+      MacroAssembler* masm,
+      Type type,
+      StrictModeFlag strict_mode = kInvalidStrictFlag);
+
  private:
-  class FromBits:       public BitField<ElementsKind,    0, 8> {};
+  class FromBits:       public BitField<ElementsKind,    0, 4> {};

[Jakob Kummerow, 2011/10/19 18:36:31]

why this change? (I'm not saying it's bad; it's just surprising that you've
changed one ElementsKind bit field and not the other.)

   class ToBits:         public BitField<ElementsKind,    8, 8> {};
   class IsJSArrayBits:  public BitField<bool,           16, 8> {};
   class StrictModeBits: public BitField<StrictModeFlag, 24, 8> {};
@@ -1054,11 +1069,8 @@ class FastElementsConversionStub : public CodeStub {
   }
 
   void Generate(MacroAssembler* masm);
+
   static void GenerateSmiOnlyToObject(MacroAssembler* masm);
-  static void GenerateSmiOnlyToDouble(MacroAssembler* masm,
-                                      StrictModeFlag strict_mode);
-  static void GenerateDoubleToObject(MacroAssembler* masm,
-                                     StrictModeFlag strict_mode);
 
   ElementsKind from_;
   ElementsKind to_;